Portion of a keyboard



FIG. 1 is a perspective view of the portion of a keyboard showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is an elevational view of the front side thereof;

FIG. 4 is an elevational view of the rear side thereof; and,

FIG. 5 is a side elevational view of the left side thereof.

The designations of front, rear and left are for reference purposes only. The broken line showing of the circular buttons in the claimed region and the remainder of the keyboard is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a portion of a keyboard, as shown and described. 